Well after all this time I finally got the car on a dyno. I'm a little disappointed, but I'll get there. We put down 492.34 RWHP and 473 FTLBS. I was hoping for bigger numbers. Considering it's an untouched mail order tune from MADWOLF i can't be too disappointed. I was unable to get a Datamaster run on it because I could'nt find by USB adapters power cable. Then we discovered an oil leak from the opti seal or somewhere around there and when it hit the balancer it would spray everywhere. I gotta work on the crankcase evac sysem too. Not getting enough ventilation I'm sure of it. Gonna do the same thing NASTY TA did and see how that works. If you know way's of getting more power to the ground I'd be happy to listen to ya. Thanks guys and have a great day.

 

is your sig correct -- 18psi on a 383? That doesn't seem right...

 

What does your converter actually stall at? A loose converter drastically effects dyno numbers. Commonest reason on these cars for low dyno numbers is knock retard.

Rich

 

stock heads?

 

His sig says stock heads ported and polished.

 

It helps if I can read

 

Upgrading from the stock heads to a good set of ported aftermarket heads will give you HUGE gains in your car. Also, I would reccomend getting it dyno tuned by a pro like Bryan Herter (PCM's for less) instead of a mail order tune.

 

My advice is just be patient. That combo has a lot of potential, 600+ rwhp.

 

i would disagree with the statment he will gain huge HP by going with aftermarket heads over stock ported ones....Heads do not have a HUGE impact on FI cars as they do on NA cars....yes there are going to be gains, but not worth 2k, unless u are trying to squeze every bit out of the car and money is unlimited.

 

i'd agree with you on a 355, but bigger cubes need more flow.

the auto & stall has a lot to do with the low numbers, but there's not enough info to really know why it's under 500 at the wheels now. How loose is the stall? what's the A/F look like? How much timing? etc...

 

I beg to differ. I have been told that switching from my AFR 180's (ported by TPIS) to some fully ported TFS, or 210 equivilant will gain me substantial gains upward of 80 RWHP alone in my car. Now consider if I had stock heads to begin with, and then changed, the gains would be even larger. Check around in this forum and you will find several people with first hand experience that heads DO infact have a large impact on forced induction cars, if not MORE than they do on N/A cars.

 

i would like to see some prove to that...there are planty of guys making over 600+ rwhp on stock ported lt1 heads...myself included...my car made 640 rwhp 595 rwtq with stock ported lt1 heads and cc305 cam at 14 psi.....There is no way it will gain 80 rwhp with swaping the heads...that would put me over 700rwhp...If it was that simple i am sure we would see a lot more people putting down over 700rwhp....I am pretty sure there are only a handfull of people with LT1s puttin down over 700rwhp with blowers alone....

 

All I can attest for is for is what I have heard repeatedly on this board, been told by several engine builders, and reputable tuners, as well as people who have done it. I myself have not changed heads with my blower application, so I do not have first hand experience. But if all who I have talked to and have heard from are incorrect, then I guess that is where I am as well. As for the numbers, I think you will find the majority of people with blown LT1 applications attaining power levels over 550 RWHP are using aftermarket heads.

It sounds like on this matter we will have to agree to disagree.

 

do you have any links to those "rumors"? i know i was in the same spot few months ago when i had my engine apart, i could not find anywhere where someone would recommened dumping a lot of money into heads on a FI car. the gains you would see over a good ported lt1 head are not worth it for the money you have to spend....its easier and cheaper to build up the bottom end and crank up the PSI vs dumping the money into heads.....

 

Sorry for getting off the original topic... but heads do make a tremendous difference.

When it comes to head flow and power, the same principles that apply to N/A applications apply here. The more fuel and air that gets into the cylinders, the more power you're going to be able to make.

Now, thinking Forced Induction... Where you might fit x amount of air into the cylinders at 14psi, those with a nice ported set of aftermarket heads may be able to get the same amount of air into the cylinders with less pressure, say 10psi. This is how we come up with boost as a measure of restriction, and generally that restriction is in the heads.

Even with the same amount of air entering the cylinders from the 14psi stock heads or the 10psi boosted heads, you're still going to see a power difference. The setup making 10psi will be more efficient and make more power because the setup making 14psi is spending extra energy to build more pressure.

Next, bump the pressure in the 10psi ported aftermarket head setup to 14psi and you gain significant power at the same "boost level" (again, generic term used to measure flow restriction).